Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
  • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
  • C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors

Definitions

• the present invention relates to an anti-corrosion composition as a new industrial product. It further relates to the method for preparing said composition and to its application in the protection of metallic surfaces, and in particular against corrosion caused by water in liquid or steam form.
• Such conditionings may be done with many mineral substances such as phosphates, polyphosphates, chromates, silicates, nitrites, sulfites, etc., or with organic ones, such as thiols, thiazols, amines, tannins, etc.; and selected as a function of the characteristics of the water used and of the installations proper.
• mineral substances such as phosphates, polyphosphates, chromates, silicates, nitrites, sulfites, etc.
• organic ones such as thiols, thiazols, amines, tannins, etc.
• amines phosphorous derivatives are found for example amines phosphorous derivatives, as well as amines proper.
• phosphorous derivatives recommended as anti-corrosion agents are aminophosphonic acids and their water-soluble salts described in French Pat. Nos. 1,430,798, 1,453,022, 1,461,087, and 1,474,068 and in published French Applications Nos. 2,060,416, 2,144,900, 2,148,260, 2,174,091, 2,184,939, 2,184,940 and 2,259,105.
• the said documents give the specific conditions in which the said aminophosphonic acids should be stoichiometrically neutralized with mineral or organic bases, and should be associated with salts that are soluble in water containing polyvalent metallic cations, such as certain zinc or chromium salts, and associated with certain organic inhibitors containing sulphur. It should however be noted that the aminophosphonic acids described previously are still presented and used in the form of water-soluble compounds to produce effects reducing the corrosion of metals to a loss of thickness always greater than or equal to 100 ⁇ /ann., at a dose of 5 ppm, and particularly with ferrous metals.
• amines have also been proposed as anti-corrosion agents, which have a molecular weight less than 300; these are ammonia, hydrazine, alkylamines (and in particular in C 1 -C 4 ), morpholine, benzylamine, cyclohexylamine, alkanolamines (see for example published French Patent Application No. 2,310,420) and polyalkylenepolyamines (see for example U.S. Pat. Nos. 3,069,225 and 2,857,333 and Dutch Pat. No.
• fatty alkylamines in C 12 -C 22 have been recommended and in particular that of dehydroabietylamine, larylamine, and stearylamine and their acid addition salts with HCl and CH 3 COOH, as well as of aliphatic polyamines with long chains known as "fatty polyamines" (see French Pat. No. 1,435,023), such as stearylaminopropyleneamine.
• fatty polyamines see French Pat. No. 1,435,023
• the disadvantage with these fatty alkylamines and polyamines is that they give an inadequate inhibition against corrosion produced by water, since the loss of thickness of the metallic surfaces (and particularly Fe or Cu surfaces) is of the order of 80 to 100 ⁇ /ann. in the best conditions of use.
• the inhibitors of the prior art and their salts lead at the most to a loss of thickness of between 80 and 150 ⁇ /ann.
• Another object of the invention is to propose a new anti-corrosion composition with an anti-corrosion power greater than that of the means recommended before. Indeed, in a large number of cases, the rates of residual corrosion through water (loss of thickness between 80 and 150 ⁇ /ann.) are still judged to be too high considering the repair and maintenance costs of the installations and considering the production or operation stoppages often necessitated by such repairs or by replacements. For example, compared with the solution proposed in published French Patent Application No.
• the present invention proposes a new anti-corrosion composition containing at least a polyamine and at least an alkylenephosphonic acid derivative, with which composition it is possible to reach, for metal surfaces needing to be protected from water for example, losses of thickness below, or equal to 50 ⁇ /ann.
• aminoalkylenephosphonic acid derivatives are meant here acids, salts and esters with, in their molecule, at least a fragment ##STR1## (wherein the alkylene group has a straight or branched hydrocarbon chain, and the dotted lines are bonds with other groups) as indicated in French Pat. No. 1,430,798.
• alkylenepolyphosphonic acid derivative is meant here a compound with at least two phosphonic functions and which is particularly selected from the group constituted by the alkylenepolyphosphonic acids, their esters and their mineral salts (such as for example metallic salts and NH 4 + ), the alkylene chain containing no amino group.
• the anti-corrosion composition according to the invention which comprises at least a polyamine and at least an alkylene-phosphonic acid derivative is a water-insoluble composition containing;
• R is a saturated or unsaturated aliphatic C 12 -C 22 hydrocarbon radical; and n 1 is an integer varying between 1 and 7 inclusive, R and n 1 being such that the molecular weight of the said polyamine is greater than or equal to 320; and
• suitable polyamines of formula I can be mentioned dodecyltri(aminopropylene)amine, dodecyltetra(aminopropylene)amine, hexadecyltri(aminopropylene)amine, hexadecenyltetra(aminopropylene)amine, octadecylaminopropyleneamine, octadecylpenta(aminopropylene)amine, octadecenyltetra(aminopropylene)amine, octadecyltri(aminopropylene)amine, octadecenylhexa(aminopropylene)amine, and hexadecylhepta(aminopropylene)amine.
• the amines of formula I may be used such as they are found in the trade, either on their own or mixed together, in their pure or technical form. It is also possible to use polyamines prepared from fatty acids of animal or vegetable origin or polyamines of synthesis. Amongst suitable polyamines, found on the market are the products known under the trademarks DIOMEEN, DINORAM, TRINORAM, POLYRAM, LILAMIN and CEMULCAT, which contain at least a polyamine I, with a molecular weight greater than or equal to 320.
• Alk is an alkylene group in C 1 -C 6 with a straight or branched hydrocarbon chain
• n 2 is an integer varying between 1 and 6 inclusive;
• Z 1 is H or an alkyl group in C 1 -C 5 ;
• Z 2 is an alkylene group in C 2 -C 5 ;
• Z 3 is an alkylene group in C 3 -C 5 ;
• n 3 is an integer varying between 1 and 20 inclusive, and
• n 4 is an integer varying between 1 and 4.
• acids of formula II the following can be mentioned by way of example and non-restrictively: aminotri(methylphosphonic)acid, aminotri(ethylphosphonic)acid, aminotri(butylphosphonic)acid, aminotri[( ⁇ , ⁇ -dimethyl)methylphosphonic]acid.
• acids of formula V the following can be cited by way of example and non-restrictively, diethoxypropylaminodi(methylphosphonic)acid, undecaethoxypropylaminodi(ethylphosphonic)acid and pentapropoxypropylaminodi(methylphosphonic)acid.
• A is a bivalent alkylene group comprising a straight and saturated C 1 -C 10 hydrocarbon chain, each carbon atom of which chain can be, if necessary, substituted by at least a group selected from the OH, C 1 -C 4 -alkyl and phosphonic groups ##STR4## and M 1 , M 2 , M 3 , M 4 , M 5 and M 6 , whether identical or different are each H, an alkyl group in C 1 -C 4 , NH 4 + or a metal cation.
• Suitable groups A are the --(CH 2 ) m [wherein m is an integer with a value varying between 1 and 10], ##STR5## wherein p is an integer with a value varying between 0 and 8.
• Other suitable groups A are given hereinafter.
• the preferred ones are the salts NH 4 + and salts of monovalent metals such as alkaline metals Na and K.
• alkylenepolyphosphonic acids (M 1 ⁇ M 2 ⁇ M 3 ⁇ M 4 ⁇ M 5 ⁇ M 6 ⁇ H), in particular alkylenediphosphonic, alkylenetriphosphonic and alkylenetetraphosphonic acids.
• Alkylenephosphonic acids answering to the aforesaid formulae II to VI may be chemically pure substances or technical products normally manufactured industrially and commercialized in liquid, paste or powder form, or even in aqueous solution form at any concentration, without the choice of one of these forms in any way constituting a restriction to the invention.
• the alkylenephosphonic acids commercialized in aqueous solution forms are preferred.
• composition according to the invention will contain (a) 5 to 80 parts by weight of polyamine I and (b) 20 to 95 parts by weight of the alkylenephosphonic acid derivative and, preferably (a) 15 to 70 parts by weight of polyamine I and (b) 30 to 85 parts by weight of derivative of the alkylenephosphonic acid of formulae II to VI.
• the method for preparing the anti-corrosion composition is performed in a manner known per se which consists in mixing one or more polyamines I with one or more derivatives of alkylenephosphonic acid.
• the method used is characterized in that the polyamine or polyamines selected is/are brought to a liquid state by adequate heating, and then introduced progressively whilst slightly or strongly stirred, depending on the case, in an aqueous solution of the alkylenephosphonic acid(s), selected, heated beforehand to a temperature less than that of the polyamine.
• the resulting mixture may be in gel, or paste or wax form.
• the polyamine(s) will be melted at a temperature varying between 30° and 85° C. approximately, and then poured into the alkylenephosphonic acid(s) brought to a temperature varying between 15° and 60° C.
• mixtures, with higher softening points will be preferred as anti-corrosion agents for metallic surfaces subjected to high temperatures, such as for example those found in steam boiler tubes or superheater tubes, or else those found in the cooling circuits of furnaces used in metallurgy and siderurgy.
• the paste or gel compositions, produced according to the invention can be introduced, by means of a conventional volumetric piston pump, either as they stand in the water of the industrial or private building systems requiring protection, or dispersed in a larger quantity of water using one or more surface active substances found on the market and known to any one skilled in the art as capable of dispersing fatty polyamines.
• the quantities of substances with surface-active properties used to this effect are dependent on the commercial aspect wanted for such dispersions and could not in any way constitute a restriction of the present invention.
• an anticorrosion composition according to the invention which composition can take the form of an aqueous bath, if necessary.
• non-ionic and/or cationic surface-active agents include those included preferably in the group of non-ionic and/or cationic surface-active agents.
• suitable non-ionic substances are ethoxylated or propoxylated fatty acids and alcohols, ethoxylated fatty monoamines, esters of fatty acids or alcohols, aliphatic amine oxides, sorbitol esters, etc.
• suitable, so-called cationic substances are amines salts, quaternary ammonium salts, products resulting from the condensation of ethylene oxide or propylene oxide with fatty polyamines.
• Stable dispersions in water may be obtained for example with industrial products selected from those known under the trademarks: NORAMOX, ETHOMEEN, DINORAMOX, ETHODUOMEEN, ETHOQUAD, ARQUAD, NORAMIUM, NOXAMINE, ADOGEN, ELFAPUR, AROMOX, etc.
• the resulting paste composition whose solubility is less than 1% by weight in distilled water, is an excellent anti-corrosion agent according to the invention, as will be seen hereinafter.
• the paste obtained after a return to room temperature appears, when thorougly examined, as a reverse dispersion of water in a yellow amber organic phase, which is found to have but a very low degree of solubility in water.
• Such composition is an excellent anti-corrosion agent as the experiments described hereinafter have proved.
• a homogeneous gel of yellow amber color is instantly obtained, which gel has a very small degree of solubility in water, but despite this fact, constitutes an excellent anti-corrosion agent for steel, copper, and aluminium in the presence of water.
• the circuit which is mainly made of glass, with a total capacity of 19.6 liters, and topped with an expansion vessel open at the top, also made of glass and with a contents capacity of 5 liters, is provided with an adjustable draining tap, that may be used discontinuously for heating tests and continuously for cooling tests.
• the flow rate of 1.6 m 3/hr is ensured by a centrifugal pump (for example one such as manufactured by the company HALBERG GmbH of Ludwigshafen, West Germany) and is controlled with a rotameter.
• the straight portions of the circuit are tubes of industrial glass, whose diameter is 40 mm and whose total length is 3 meters.
• the flowing speed of the water is about 1.5 meters per second.
• Said circuit further comprises means for controlling the efficiency of the inhibitors:
• a double probe connected to an electronic analyzer of the CORRATER type (commercialized by the company MAGNE INSTRUMENTS ROHRBACK CORP. of Santa Fe Springs, Ca.), provided with a recorder for potentio-static measurements of corrosion speed, and with a converter for alternatively measuring the so-called “generalized” corrosion and the corrosion known as "pitting".
• the specific electrodes of the potentio-static CORRATER analyzer have the references 60814-8001 for measurements effected on steel, 60814-8061 for measurements effected on copper, and 60814-8080 for measurements effected on aluminium.
• test pieces for measuring the weight losses are cylinder-shaped and hollow, 50 mm long, with an outer diameter of 21.3 to 22 mm, and an inner diameter of 14.8 to 17 mm, and with an external surface of 33.45 to 34.55 cm2, in contact with the attacking medium, and weighing in average 72.5 g for the steel pieces, 69 g for the copper pieces and 21.2 g for the aluminium pieces.
• the metal pieces are polished with a mild abrasive normally found on the market, washed in distilled water, dried in ketone and weighed with accuracy at ⁇ 1 ⁇ 10 -4 g. They are then mounted in series, three by three, each of a different metal, at a distance from one another and held together in position by an appropriate system in Teflon, and then introduced horizontally in a straight glass portion of the circuit. After the tests, they are removed from the circuit, brushed with a soft brush to remove all corrosion products, and washed in distilled water, dried in ketone and weighed very accurately at ⁇ 1 ⁇ 10 -4 g.
• the tests were carried out with four different varieties of water, namely tap water (tap water A1 for the anti-corrosion compositions of Examples 1-3, and tap water A2 for the anti-corrosion compositions of Examples 4-6) and soft water (soft water B1 for the anti-corrosion compositions of Examples 1-3, and soft water B2 for the anti-corrosion compositions of Examples 4-6), the soft waters B1 and B2, respectively, being obtained from the tap waters A1 and A2 respectively by passage over a ion-exchanging resin, of the cationic type in sodium cycle.
• tap water tap water A1 for the anti-corrosion compositions of Examples 1-3, and tap water A2 for the anti-corrosion compositions of Examples 4-6
• soft water soft water B1 for the anti-corrosion compositions of Examples 1-3, and soft water B2 for the anti-corrosion compositions of Examples 4-6
• Tap waters A1 and A2 (drinkable waters distributed by the city of PARIS) were used as they are for corrosion tests of the "cold” type and soft waters B1 and B2 were used for the corrosion tests of the "heat" type.
• d specific mass of the metal of the test piece given in g/cm3.
• Tables II to V relate to the measurements of weight losses, and Tables IV and V to the potentiostatic measurements for assessing the speeds of corrosion (expressed in microns per annum).
• control measurements i.e. measurements without inhibitor
• the measurements in the presence of the inhibitor where carried out for two months, for each composition tested and at two different dosages, within an approximate ratio of 10 to 1, depending on the mechanical possibilities of dispersion in the water of the compositions of Examples 1 to 6 above, without a surface-active agent having been used.
• the circuit has been modified by the introduction into its straight portion of a hollow steel probe, of 240 mm long and with an outside diameter of 28 mm, provided with a heating element which is adjustable by way of the rheostat.
• the metal test pieces for measuring the weight losses and the "CORRATER” probe are retained, as with the "HEAT" type tests.
• the circuit is filled and then supplied continuously with tap water from the city of PARIS, having the characteristics indicated in TABLE I and at the rate of about 20 liters per hour, entailing the renewing of the circuit water every hour in average.
• the drainage is controlled continuously so that the water level in the expansion vessel is kept constant.
• the anti-corrosion paste, according to the compositions of the invention is simply immersed in the expansion vessel by means of a linen bag.
• the temperature of the water, kept in forced circulation by the centrifugal pump and measured by a thermometer placed upstream of the heated probe, is stabilized at 50° C. ⁇ 5° C.
• Each test lasts 15 days with or without the inhibitors of Examples 1 to 6 above.
• the same measurements are carried out as for the "HEAT" type tests, with the only difference that at the end of the tests, the cylindrical test pieces in steel, copper and aluminium, as well as the heated probe made of steel, are washed before being brushed, with a diluted solution of passivated sulfamic acid, before removing any possible deposits of mineral salts that could be due to the hardness of the tap water and which the phosphonic acids, present in possibly insufficient quantities in the compositions according to the invention, could not have prevented.
• Tables VI to IX relate to the measurement of weight losses and Tables VIII and IX to potentiostatic measurements for assessing the speeds of corrosion.
• test pieces As well as the heated probe, appear to be coated with a very fine white powder which is removed easily with a soft brush, even from the heated probe.
• a rince in diluted sulfamic acid is nevertheless done as a precaution measure.
• a microscope examination shows that all the test pieces and the heated probe are completely pitting-free.
• the steel test-pieces are smooth, of a brownish color, more pronounced than on the heated probe.
• the copper and aluminium test pieces are a little less shiny than in the "HEAT" type tests.
• the other metallic elements of the circuit appear after dismantling, brushing and rincing in sulfamic acid, totally free of any deposits of corrosion and of any visible corroding.
• Examples 1 to 6 and Tables II to IX also show that important variations in the nature and respective proportions of the constituants of the compositions according to the invention have no significant effect on the anti-corrosion properties thereof. It is also a remarkable fact that the compositions according to the invention require no adjustment of the pH of the corrosive medium nor the addition of specific inhibitors, for copper for example. It is finally remarkable that in doses of 5 parts per one million, the compositions according to the invention show an anti-corrosion power that is clearly greater than the anti-corrosion powers of each of their constituents, taken separately, in substantially higher doses.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
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• Organic Chemistry (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)

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• 1979
  • 1979-10-09 DE DE7979400727T patent/DE2962827D1/de not_active Expired
  • 1979-10-09 EP EP79400727A patent/EP0010485B1/fr not_active Expired
  • 1979-10-10 US US06/083,553 patent/US4276089A/en not_active Expired - Lifetime
  • 1979-10-12 CA CA337,470A patent/CA1122394A/fr not_active Expired
  • 1979-10-12 BR BR7906560A patent/BR7906560A/pt unknown
  • 1979-10-13 OA OA56913A patent/OA06353A/fr unknown
  • 1979-10-15 DD DD79216235A patent/DD146629A5/de unknown

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